/**
 * Copyright (C) 2007, 2008 Carnegie Mellon University and others.
 *
 * This file is part of Plural.
 *
 * Plural is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Plural is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Plural; if not, see <http://www.gnu.org/licenses>.
 *
 * Linking Plural statically or dynamically with other modules is
 * making a combined work based on Plural. Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * In addition, as a special exception, the copyright holders of Plural
 * give you permission to combine Plural with free software programs or
 * libraries that are released under the GNU LGPL and with code
 * included in the standard release of Eclipse under the Eclipse Public
 * License (or modified versions of such code, with unchanged license).
 * You may copy and distribute such a system following the terms of the
 * GNU GPL for Plural and the licenses of the other code concerned.
 *
 * Note that people who make modified versions of Plural are not
 * obligated to grant this special exception for their modified
 * versions; it is their choice whether to do so. The GNU General
 * Public License gives permission to release a modified version
 * without this exception; this exception also makes it possible to
 * release a modified version which carries forward this exception.
 */

package edu.cmu.cs.plural.test;

import edu.cmu.cs.crystal.annotations.FailingTest;
import edu.cmu.cs.crystal.annotations.UseAnalyses;
import edu.cmu.cs.plural.annot.Full;
import edu.cmu.cs.plural.annot.Pure;
import edu.cmu.cs.plural.annot.TrueIndicates;

/**
 * This is a stream-like test class for
 * splitting off pure permission for bigger roots.
 * Unlike other permissions, pure permissions for
 * bigger roots can be split off without having to
 * move the root of the available permission up.
 * @author Kevin Bierhoff
 * @since 4/14/2008
 */
@FailingTest(1)
@UseAnalyses("FractionalAnalysis")
public abstract class SplittingPure {
	
	@Full(ensures = "closed")
	public abstract void close();
	
	@Pure
	@TrueIndicates("open")
	public abstract boolean isOpen();
	
	@Pure
	@Override
	public String toString() {
		return isOpen() ? "yep" : "ney"; // legal: same root
	}
	
	@Pure("open")
	public int available() {
		if(isOpen()) // legal: can split off pure permisson for bigger root
			return 0;
		// impossible branch (not currently detected)
		throw new IllegalStateException("Closed.");
	}
	
	@Full("open")
	public String readMe() {
		return toString(); // legal: can split off pure permission for bigger root
	}
	
	@Full("open")
	public void dangerous() {
		close(); // illegal: need full permission for bigger root
	}
	
}
